Keyswitch structure

ABSTRACT

A keyswitch structure includes a base plate, a keycap, a scissors support connecting the keycap and the base plate, a linking support rotatably disposed on the base plate, a movable part movably disposed relative to the base plate, and a magnetic part on the movable part. The linking support includes a magnetic portion and a driving portion. The magnetic part and the magnetic portion produce a magnetic attraction force therebetween. When the movable part is located at a first position, the magnetic part is located under the magnetic portion, and the magnetic attraction force drives the keycap through the linking support to move away relative to the base plate. When the movable part moves from the first position to a second position, the magnetic part moves away relative to the magnetic portion, so that the magnetic attraction force decreases so as to make the keycap move toward the base plate.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a magnetic keyswitch, and more particularly to a magnetic keyswitch of which the keycap can be moved downward for storage.

2. Description of the Prior Art

The keyboards of conventional notebook computers are not designed to have keycaps that can be moved downward for storage. No matter whether the display screen is open or closed, the keycaps are located at the same height (i.e. the position when unpressed). Thereby, the height of the conventional keyboard is fixed. When a user has no need to use the notebook computer, the user will close the display screen. Because the keycaps of the conventional notebook computer does not move downward for storage, the display screen may impact the keycaps and therefore get damaged. Furthermore, the keyboard occupies relatively more space, which limits the thinner development of the notebook computer. Furthermore, if the keyswitch of the keyboard is designed to use an elastic member (e.g. a rubber dome) for providing a restoration force to the keycap, when the keycap is forced to move downward for storage, the elastic member, in principle, will be at a status of being pressed for a long time, which may induce a permanent deformation affecting the elasticity of the elastic member and harmful to the lifespan of the elastic member.

SUMMARY OF THE INVENTION

The present disclosure provides a keyswitch structure, which is operable to increase the distance between two magnetic parts used for providing a restoration force to a keycap of the keyswitch structure, so that the keycap can move downward for storage.

A keyswitch structure according to the present invention includes a base plate, a keycap, a scissors support, a linking support, a movable part, and a magnetic part. The keycap is disposed above the base plate. The scissors support is connected to and between the base plate and the keycap. The keycap can move relative to the base plate substantially along a vertical direction through the scissors support. The linking support is rotatably disposed on the base plate and has a magnetic portion and a driving portion. The driving portion abuts against one of the scissors support and the keycap. The movable part is movably disposed relative to the base plate substantially along a horizontal direction. The magnetic part is disposed on the movable part. The magnetic portion and the magnetic part producing a magnetic attraction force therebetween. Therein, when the movable part is located at a first position, the magnetic part is located under the magnetic portion, and the magnetic attraction force drives the keycap through the linking support to move away relative to the base plate. When the movable part horizontally moves from the first position to a second position, the magnetic part moves away relative to the magnetic portion, so that the magnetic attraction force decreases to make the keycap move toward the base plate.

Compared with the prior art, in the keyswitch structure according to the present invention, the keycap can move downward for storage even though the keycap does not receive external pressing force thereon. Furthermore, the restoration force (i.e. the magnetic attraction force) to the keycap is not produced by an elastic structure, so the keyswitch structure will not have the problem in the prior art that the elastic member may involve a permanent deformation affecting the elasticity of the elastic member.

These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating a keyswitch structure of an embodiment according to the invention.

FIG. 2 is a partially-exploded view of the keyswitch structure in FIG. 1.

FIG. 3 is another partially-exploded view of the keyswitch structure in FIG. 1.

FIG. 4 is an exploded view of the keyswitch structure in FIG. 1.

FIG. 5 is a schematic diagram illustrating FIG. 4 in another view.

FIG. 6 is an exploded view of a linking support of the keyswitch structure in FIG. 3.

FIG. 7 is a schematic diagram illustrating FIG. 6 in another view.

FIG. 8 is a sectional view of the keyswitch structure along the line X-X in FIG. 1.

FIG. 9 is a sectional view of the keyswitch structure along the line Y-Y in FIG. 1, of which the cutting plane passes through a constraint structure of a base plate of the keyswitch structure.

FIG. 10 is a sectional view of the keyswitch structure in FIG. 8 when the keycap is pressed.

FIG. 11 is a sectional view of the keyswitch structure in FIG. 8 at a storage status.

FIG. 12 is a sectional view of the keyswitch structure in FIG. 8 according to another embodiment.

FIG. 13 is a side view of the keyswitch structure in FIG. 1 at the storage status; therein, the profile of the keycap is shown in dashed lines.

FIG. 14 is a partially-exploded view of a keyswitch structure according to another embodiment.

FIG. 15 is an exploded view of the keyswitch structure in FIG. 14.

FIG. 16 is a schematic diagram illustrating FIG. 15 in another view.

FIG. 17 is a sectional view of the keyswitch structure in FIG. 14.

FIG. 18 is a side view of the keyswitch structure in FIG. 14 at a storage status; therein, the profile of the keycap is shown in dashed lines.

DETAILED DESCRIPTION

Please refer to FIG. 1 to FIG. 10. A keyswitch structure 1 according to an embodiment includes a base plate 10, a keycap 12, a scissors support 14, a movable part 16, a linking support 18, a magnetic part 20, and a switch circuit board 22. The keycap 12 is disposed above the base plate 10. The scissors support 14 is disposed between the base plate 10 and the keycap 12, so that the keycap 12 can move relative to base plate 10 substantially along a vertical direction D1 (indicated by a double-head arrow in FIG. 1 and FIG. 8 to FIG. 10) through the scissors support 14. The movable part 16 is movably disposed relative to the base plate 10 substantially along a horizontal direction D2 (indicated by a double-head arrow in FIG. 1 and FIG. 8 to FIG. 10). The linking support 18 has a pivotal connection portion 182, a magnetic portion 184, and a driving portion 186. The pivotal connection portion 182 extends through the linking support 18 to two opposite sides of the linking support 18. The magnetic portion 184 and the driving portion 186 are located at opposite sides of the pivotal connection portion 182. The linking support 18 is rotatably disposed on the base plate 10 through the pivotal connection portion 182. The driving portion 186 abuts against the scissors support 14. The magnetic part 20 is disposed on the movable part 16 and under the magnetic portion 184. The magnetic portion 184 and the magnetic part 20 produce a magnetic attraction force F (indicated by a double-head arrow in FIG. 8 and FIG. 10) therebetween. The movable part 16 is operable to horizontally move relative to the base plate 10 to change the horizontal position of the magnetic part 20 relative to the base plate 10. In FIG. 1, FIG. 2, FIG. 8 and FIG. 10, the movable part 16 is located at a first position, and the keyswitch structure 1 is at a status of being capable of being pressed by user. The magnetic attraction force F makes the magnetic portion 184 lower, so as to make the linking support 18 rotate around the pivotal connection portion 182 to drive the driving portion 186 to move upward, so that the keycap 12 is lifted to move away relative to the base plate 10. The switch circuit board 22 has a switch 222 (shown by a hatched circle in FIG. 4 and by a rectangle in FIG. 8 and FIG. 10) and is disposed on the movable part 16 to be movable together with the movable part 16. When the keycap 12 is pressed down, the switch 222 is triggered. When the keycap 12 is not pressed any more, the magnetic attraction force F serves as a restoration force to make the keycap 12 move upward to return its original higher position.

In the embodiment, the scissors support 14 includes a first support 142 and a second support 144. The first support 142 and the second support 144 are pivotally connected relative to a rotation axis 14 a (indicated by a chain line in FIG. 2 and FIG. 3). The rotation axis 14 a is perpendicular to the vertical direction D1 and the horizontal direction D2. The first support 142 is connected to a first keycap connection portion 122 of the keycap 12 (realized by two sliding slots which protrude downward from a bottom surface 120 a of a cap body 120 of the keycap 12) through a first upper end portion 1422 and is connected to a first base plate connection portion 102 of the base plate 10 (realized by two L-shaped hooks) through a first lower end portion 1424. The second support 144 is connected to a second keycap connection portion 124 of the keycap 12 (realized two droplet-shaped holes which protrude downward from the bottom surface 120 a of the cap body 120) through a second upper end portion 1442 and is connected to a second base plate connection portion 104 of the base plate 10 (realized by two L-shaped hooks) through a second lower end portion 1444. Thereby, the keycap 12 can vertically move relative to the base plate 10 through the first support 142 and the second support 144.

The linking support 18 includes a plastic part 18 a and a paramagnetic plate 18 b. The paramagnetic plate 18 b fits in the plastic part 18 a. In practice, it is practicable to join the paramagnetic plate 18 b into the plastic part 18 a by insert moulding, so that the plastic part 18 a can be provided with less opening so as to enhance the structural strength of the plastic part 18 a. The plastic part 18 a forms the driving portion 186 and the pivotal connection portion 182. The paramagnetic plate 18 b forms the magnetic portion 184. The pivotal connection portion 182 is pivotally connected to two constraint structures 106 of the base plate 10 through two end portions 182 a of the pivotal connection portion 182. Therein, the constraint structure 106 includes an L-shaped hook 1062 and a limitation post 1064. The corresponding end portion 182 a is limitedly and rotatably disposed between the L-shaped hook 1062 and the limitation post 1064, as shown by FIG. 9. The driving portion 186 abuts upward against a portion of the second support 144 close to the second upper end portion 1442. Furthermore, the plastic part 18 a also forms a triggering portion 188 toward the base plate 10. As shown by FIG. 10, the magnetic portion 184 and the triggering portion 188 are located at two sides of the pivotal connection portion 182. The switch 222 is located under the linking support 18 (or the triggering portion 188 thereof). When the keycap 12 is pressed, the triggering portion 188 triggers the switch 222.

The movable part 16 includes a movable plate 162 and a constraint structure 164 (realized by two opposite structures that extend upward and bend) disposed on the movable plate 162. The movable plate 162 is movably disposed under the base plate 10. The magnetic part 20 is a magnet and is fixed on the movable part 16 through the constraint structure 164. The switch circuit board 22 is disposed on the movable plate 162 under the base plate 10. The base plate 10 has an opening corresponding to the switch 222 so as to expose the switch 222; thereby, the linking support 18 (or the triggering portion 188 thereof) above the base plate 10 can rotate relative to the base plate 10 to trigger the switch 222. In practice, the switch circuit board 22 can be realized by but not limited to a conventional three-layered membrane circuit board of (of which the upper and lower layers carry circuitry, and of which the middle layer insulates the circuitry on the upper and lower layers). For simplification of drawings, the switch circuit board 22 is still shown by a single part. For example, the switch circuit board 22 can be realized by a printed circuit board or a flexible printed circuit, on which a tact switch (serving as a mechanical switch 222) or a combination a light source and an optical sensor (serving as an optical switch 222) is soldered.

In addition, in practice, for example, the base plate 10 can be realized by but not limited to a metal stamping part, in which the first base plate connection portion 102, the second base plate connection portion 104, and the L-shaped hook 1062 are formed by bending L-shaped plates upward and the limitation post 1064 is formed by bending plate portions upward. Each of the keycap 12, the first support 142, and the second support 144 can be realized by an injection plastic part. The movable part 16 can be realized by a metal stamping part, of which the constraint structure 164 is formed by bending a portion of the metal stamping part upward. In addition, in practice, the linking support 18 as a whole also can be realized by a paramagnetic metal stamping part. In another case, when the magnetic portion 184 is realized by a magnet, the magnetic part 20 can be realized by a part made of a paramagnetic material.

Please refer to FIG. 8 and FIG. 11. When the movable part 16 substantially horizontally moves (or moves rightward) from the first position (as shown by FIG. 8) to a second position (as shown by FIG. 11), the magnetic part 20 also horizontally moves together with the movable part 16 away relative to the magnetic portion 184 (or depart away from the position under the magnetic portion 184), so that the magnetic attraction force F decreases so as to make the keycap 12 move toward the base plate 10, for convenience of storage. As shown by FIG. 11, the keyswitch structure 1 is at a storage status. The switch circuit board 22 moves together with the movable part 16, so that when the movable part 16 is located at the second position, the switch 222 is away from a projection area where the triggering portion 188 is projected downward along the vertical direction D1. Therefore, when the keyswitch structure 1 is at the storage status, the triggering portion 188 will not compress the switch 222, which can avoid applying force to the switch 222 for a long time so as to effectively prolong the lifespan of the switch 222. In practice, the magnetic attraction force F can be designed to be unable to resist the weight of the scissors support 14 and the keycap 12 when the movable part 16 is located at the second position, so that the keyswitch structure 1 collapses to be at the storage status. In other words, at this moment, the magnetic attraction force F is insufficient to keep the linking support 18 at the status as shown by FIG. 8, or to support the scissors support 14 and the keycap 12 to keep at the higher position (or the position where the keycap 12 cannot be moved upward), so that the keyswitch structure 1 collapses to be at the storage status. In the embodiment, when the movable part 16 is located at the second position, the magnetic part 20 is under the pivotal connection portion 182, as shown by FIG. 11. At the moment, the magnetic attraction force F substantially can hardly provide enough torque to the linking support 18 for maintaining the posture as shown by FIG. 8.

When the keyswitch structure 1 at the storage status (as shown by FIG. 11) is required to be changed to the status of being capable of being pressed by user, the movable part 16 can be operated to move reversely (or move leftward, i.e. substantially horizontally moving from the second position to the first position) so as to make the magnetic part 20 back to the position under the magnetic portion 184, so that the magnetic attraction force F increases and drives the linking support 18 to rotate to expand the scissors support 14 to lift the keycap 12, so that the keyswitch structure 1 can be at the status of being capable of being pressed by user (as shown by FIG. 8).

In addition, in the embodiment, when the movable part 16 is located at the first position and the keycap 12 is not pressed yet (as shown by FIG. 8), the magnetic portion 184 line-contacts the magnetic part 20, which facilitates the movement of the magnetic part 20 relative to the magnetic portion 184 and the movement of the movable part 16 as well. In practice, it is practicable to dispose the magnetic portion 184 and the magnetic part 20 to be separate from each other (i.e. when the keyswitch structure 1 is at the status of being capable of being pressed by user, the magnetic portion 184 does not touch the magnetic part 20), as shown by FIG. 12. Therein, the movable part 16 includes a stop structure 168 for blocking the magnetic portion 184 from touching the magnetic part 20. This configuration makes the movement of the movable part 16 (together with magnetic part 20) easier.

Please refer to FIG. 1 to FIG. 4, FIG. 8, and FIG. 13. In the embodiment, the keyswitch structure 1 further includes other interactive structures for facilitating keeping the keyswitch structure 1 at the storage status. Therein, the first support 142 includes two sliding slots 1426 extending along an extension direction 142 a (indicated by an arrow in FIG. 2 to FIG. 4). The extension direction 142 a points from the first lower end portion 1424 to the first upper end portion 1422. The movable part 18 includes two sliding hooks 166 corresponding to the sliding slots 1426 respectively. During the movement of the movable part 16 from the first position (as shown by FIG. 2 or FIG. 8) to the second position (as shown by FIG. 13), the sliding hook 166 slides in the corresponding sliding slot 1426 and applies a force to the sliding slot 1426 to rotate the first support 142 toward the base plate 10, so as to reduce the height of the first upper end portion 1422. Furthermore, during this movement, the decrease of the magnetic attraction force F is conducive to the rotation of the first support 142 toward the base plate 10, so the resistance to the sliding of the sliding hook 166 in the sliding slot 1426 can be reduced. Therefore, both the decrease of the magnetic attraction force F and the sliding of the sliding hook 166 in the sliding slot 1426 are conducive to keeping the keyswitch structure 1 at the storage status.

Furthermore, in the embodiment, the sliding slot 1426 includes an opening 1426 a and a slot way 1426 b. During the movement of the movable part 16 from the first position to the second position, the sliding hook 166 enters the slot way 1426 from the opening 1426 a. The slot way 1426 b has a slot bottom surface 1426 c. The slot bottom surface 1426 c extends in a direction deviating from the extension direction 142 a and toward the base plate 10. During the movement of the movable part 16 from the first position to the second position, the sliding hook 166 slides on the slot bottom surface 1426 c toward the first lower end portion 1424. Furthermore, projections in the vertical direction D1 of the sliding slot 1426 and the driving portion 186 are located at the same side of the rotation axis 14 a, which can be understood on FIG. 2 and will not be described further. Furthermore, in the embodiment, there are two of the sliding slot 1426 (and the corresponding sliding hook 166) disposed; however, in practice, it is applicable to dispose one, which still can achieve the function of collapsing the supports as described above and will not be described in addition.

Please refer to FIG. 14 to FIG. 18; therein, the position of the cutting plane of FIG. 17 is equivalent to the line X-X in FIG. 1. A keyswitch structure 3 according to another embodiment is similar to the keyswitch structure 1 and uses the reference numbers of the keyswitch structure 1. For other descriptions about the keyswitch structure 3, please refer to the relevant descriptions of the keyswitch structure 1 and variants thereof, which will not be described in addition. A difference between the keyswitch structure 1 and the keyswitch structure 3 is that the linking support 18 (or the driving portion 186 thereof) of the keyswitch structure 3 abuts directly against the bottom surface 120 a of the cap body 120. Furthermore, in the keyswitch structure 3, the projections in the vertical direction D1 of the sliding slot 1426 and the driving portion 186 are located at opposite sides of the rotation axis 14 a respectively. The slot bottom surface 1426 c extends in a direction deviating from the extension direction 142 a and toward the keycap 12. During the movement of the movable part 16 from the first position (as shown by FIG. 14) to the second position (as shown by FIG. 18), the sliding hook 166 slides on the slot bottom surface 1426 c toward the first upper end portion 1422.

Furthermore, in the keyswitch structures 1 and 3, the first support 142 is an outer ring and the second support 144 is an inner ring. The inner ring is pivotally connected to the inner side of the outer ring. The linking support 18 is located within the inner side of the inner ring. The sliding slot 1426 is disposed on the first support 142. However, it is not limited thereto in practice. For example, in the keyswitch structure 3, the second support 144 can be modified to be an n-shaped structure, such that the linking support 18 can extend outward to abut against the first support 142, and the linking support 18 will not structurally interfere with the second support 144 in a press on the keycap 12. For another example based on the keyswitch structure 1, the sliding slots 1426 of the first support 142 and the corresponding sliding hooks 166 are removed, and instead, the sliding slots 1426 and the corresponding sliding hooks 166 in keyswitch structure 3 are applied to the second support 144 herein. In this example, projections in the vertical direction D1 of the sliding slot 1426 and the driving portion 186 are located at two opposite sides of the rotation axis 14 a. The inner side of the first support 142 may need structural amendment for avoiding structural interference, which will not be described in addition. Similarly, in the keyswitch structure 3, the sliding slots 1426 of the first support 142 and the corresponding sliding hooks 166 can be removed, and instead, the sliding slots 1426 and the corresponding sliding hooks 166 in the keyswitch structure 1 are applied to the second support 144 herein.

In addition, in the keyswitch structures 1 and 3, the movable parts 16 and 36 are slidably disposed under the base plate 10; however, it is not limited thereto in practice. For example, the movable parts 16 and 36 are changed to be disposed above the base plate 10 and are provided with openings corresponding to the structures of the base plate 10 (e.g. the base plate connection portions 102 and 104, the constraint structures 106 and so on) for avoiding structural interference.

In the keyswitch structures 1 and 3, the keycap 12 still can move downward for storage even though the keycap 12 does not receive external pressing force thereon. Furthermore, the restoration force (i.e. the magnetic attraction force) to the keycap 12 is not produced by an elastic structure, so the keyswitch structures 1 and 3 will not have the problem in the prior art that the elastic member may involve a permanent deformation affecting the elasticity of the elastic member.

Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims. 

What is claimed is:
 1. A keyswitch structure, comprising: a base plate; a keycap, disposed above the base plate; a scissors support, connected to and between the base plate and the keycap, the keycap being movable relative to the base plate substantially along a vertical direction through the scissors support; a linking support, rotatably disposed on the base plate, the linking support having a magnetic portion and a driving portion, the driving portion abutting against one of the scissors support and the keycap; a movable part, movably disposed relative to the base plate along a horizontal direction; a switch, attached to the movable part and movable along with the movable part; and a magnetic part, disposed on the movable part, the magnetic portion and the magnetic part producing a magnetic attraction force therebetween; wherein when the movable part is located at a first position, the magnetic part is located under the magnetic portion, and the magnetic attraction force drives the keycap through the linking support to move away relative to the base plate; wherein the switch is triggered when the movable part is located at the first position and the keycap is pressed; and when the movable part substantially horizontally moves from the first position to a second position, the magnetic part moves away relative to the magnetic portion, so that the magnetic attraction force decreases to make the keycap move toward the base plate without triggering the switch.
 2. The keyswitch structure according to claim 1, wherein when the movable part is located at the first position and the keycap is not pressed, the magnetic portion line-contacts the magnetic part.
 3. The keyswitch structure according to claim 1, wherein when the movable part is located at the first position and the keycap is not pressed, the magnetic portion and the magnetic part are separate from each other.
 4. The keyswitch structure according to claim 1, wherein the linking support has a pivotal connection portion and is rotatably disposed on the base plate through the pivotal connection portion, the magnetic portion and the driving portion are located at two sides of the pivotal connection portion respectively, and when the movable part is located at the second position, the magnetic part is located under the pivotal connection portion.
 5. The keyswitch structure according to claim 1, wherein the switch is disposed on the movable part, the linking support has a triggering portion, when the movable part is located at the first position, the switch is located under the triggering portion, and when the movable part is located at the second position, the switch is away from a projection area where the triggering portion is projected downward along the vertical direction.
 6. The keyswitch structure according to claim 5, wherein when the movable part is located at the first position and the keycap is pressed, the triggering portion triggers the switch.
 7. The keyswitch structure according to claim 6, wherein the linking support has a pivotal connection portion and is rotatably disposed on the base plate through the pivotal connection portion, and the magnetic portion and the triggering portion are located at two sides of the pivotal connection portion respectively.
 8. The keyswitch structure according to claim 1, wherein the scissors support comprises a first support and a second support which are pivotally connected with each other, the keycap is vertically movable relative to the base plate through the first support and the second support, the first support is connected to the keycap through a first upper end portion of the first support and is connected to the base plate through a first lower end portion of the first support, and the second support is connected to the keycap through a second upper end portion of the second support and is connected to the base plate through a second lower end portion of the second support.
 9. The keyswitch structure according to claim 8, wherein the first support comprises a sliding slot, extending along an extension direction, the extension direction points from the first lower end portion to the first upper end portion, the movable part comprises a sliding hook, and during a movement of the movable part from the first position to the second position, the sliding hook slides in the sliding slot and applies a force to the sliding slot so that the first support rotates toward the base plate, so as to reduce a height of the first upper end portion.
 10. The keyswitch structure according to claim 9, wherein the first support and the second support are pivotally connected relative to a rotation axis, the driving portion abuts against the second upper end portion of the second support, and projections in a vertical direction of the sliding slot and the driving portion are located at a same side of the rotation axis.
 11. The keyswitch structure according to claim 9, wherein the sliding slot has a slot bottom surface, the slot bottom surface extends in a direction deviating from the extension direction and toward the base plate, and during a movement of the movable part from the first position to the second position, the sliding hook slides on the slot bottom surface toward the first lower end portion.
 12. The keyswitch structure according to claim 9, wherein the first support and the second support are pivotally connected relative to a rotation axis, the driving portion abuts against the keycap, and projections in a vertical direction of the sliding slot and the driving portion are located at two opposite sides of the rotation axis respectively.
 13. The keyswitch structure according to claim 12, wherein the sliding slot has a slot bottom surface, the slot bottom surface extends in a direction deviating from the extension direction and toward the keycap, and during a movement of the movable part from the first position to the second position, the sliding hook slides on the slot bottom surface toward the first upper end portion.
 14. The keyswitch structure according to claim 8, wherein the first support is an outer ring, the second support is an inner ring, the inner ring is pivotally connected to an inner side of the outer ring, and the linking support is located in an inner side of the inner ring.
 15. The keyswitch structure according to claim 1, wherein the linking support comprises a plastic part and a paramagnetic plate joined to the plastic part, the plastic part forms the driving portion, and the paramagnetic plate forms the magnetic portion.
 16. The keyswitch structure according to claim 1, wherein a horizontal movement of the movable part from the first position to the second position causes the magnetic attraction force to decrease.
 17. The keyswitch structure according to claim 1, wherein the movable part is disposed under the base plate. 